The discovery of those D.sub.3 dopaminergic receptors (P. Sokoloff et al., Nature, 1990, 347, 147), their strong concentration in the limbic system and their low density in lactotrophic cells and in the nigrostriated system, makes them a choice target for obtaining antipsychotics that do not have effects on the secretion of prolactin and are less liable to cause extrapyramidal-type syndromes. It has, in fact, been established that the dopaminergic pathways extending to the limbic system and the cortex play a decisive role in the control of mood and in the aetiology and treatment of psychiatric disorders such as schizophrenia, depression, anxiety, aggression and other impulsive disorders (M. J. Millan et al., Drug News & Perspectives, 1992, 5, 397-406 A. Y. Deutch et al., Schizophrenia, 1991, 4, 121-156; H. Y. Meltzen et al., Pharmacol. Rev., 1991, 43, 587-604).